1. Field of the Invention
The present invention relates to a liquid crystal display (LCD), and more particularly to a transflective LCD.
2. Description of the Prior Art
LCDs have been popularly applied to various IT products such as notebooks, personal digital assistants (PDAs), and cellular phones. Since LCDs are passive luminous devices, an external light source is required. According to different types of external light sources, LCDs are generally classified into reflective LCDs, transmissive LCDs, and transflective LCDs. In a reflective LCD, an external light in front of the panel enters the panel, and is reflected by a reflective layer (such as a aluminum layer) so that users can see what the LCD displays on the screen. In a transmissive LCD, a back light module is installed behind the panel for radiating light, and the radiating light will pass through the panel so that users can see what the LCD displays on the screen. In a transflective LCD, an external light and a back light module are used simultaneously as light sources to illuminate the transflective LCD.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of a pixel region 100 of a prior art transflective LCD, wherein the pixel region 100 is a red color, green color, or blue color pixel region. As shown in FIG. 1, the pixel region 100 comprises a reflection pixel region 110 and a transmission region 120, wherein the reflection pixel region 110 includes a reflective electrode (not shown), and the transmission pixel region 120 comprises a transmissive electrode (not shown). The transmissive electrode (not shown) and the reflective electrode of a pixel region are connected to a pixel driving circuit 101 controlled by a scan line SL1 and a data line DL1, and the luminance of the transmission pixel and the reflective pixel are controlled by the pixel driving circuit 101 simultaneously.
The transmission mode of the prior art transflective LCD uses an internal back light module, while the reflection mode uses an external light. However, in the prior art a pixel driving circuit is used to control both a transmission pixel region and a reflection pixel region in the same pixel region, so only the transmission region or the reflection region can be controlled to its best color display. Therefore the total color display of the transflective LCD is reduced.